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Abstract
INTRODUCTION: Type 2 diabetes is a metabolic disease primarily characterized by hyperglycemia. Hypoglycemic agents are used clinically to reduce fasting and postprandial glucose. Metformin monotherapy is the first-line therapy, and once it is no longer adequate, additional hypoglycemic agents are implemented. Postmeal exercise has been shown to attenuate glycemic excursions, and may provide additional glucose-lowering benefit beyond that of hypoglycemic agents alone. METHODS: Study 1 employed a randomized crossover design in people on metformin monotherapy to assess the effects of postmeal walking (5 x 10 min bouts at 60% VO2 max) after a standardized breakfast meal, using continuous glucose monitoring. Study 2 employed a repeated measures design to assess the effects of postmeal walking (3 x 10 min bouts at 50% VO2 max) in people on add-on hypoglycemic agents after a standardized breakfast meal. RESULTS: In people on metformin monotherapy, postmeal exercise significantly reduced 2-hr peak (p = 0.001) and 2-hr AUC (p = 0.006), with the lowest peak observed with postmeal exercise and metformin combined (p < 0.05 vs. all other conditions: met/sed: 12 3.4, met/ex: 9.7 2.3, washout/sed: 13.3 3.2, washout/ex: 11.1 3.4 mmol/L). In people on add-on therapies, glucose was reduced during postmeal exercise, including peak (drug only: 13.8 3.7 mmol/L, drug and postmeal exercise: 9.9 2.7 mmol/L; p = 0.02) and AUC (drug only: 500 136 mmol/L x 40 min, drug and postmeal exercise: 357 89 mmol/L x 40 min; p = 0.03). However, 2-hr peak and 2-hr AUC were not different between conditions. DISCUSSION: Postmeal exercise added additional glucose-lowering benefit beyond medication alone in those on metformin monotherapy, as well as those on add-on therapies. A bigger glucose-lowering effect was observed in participants on metformin monotherapy. CONCLUSION: Exercise during the postprandial phase may be important for optimizing glucose control in people on hypoglycemic agents.